1 files changed, 15 insertions, 1 deletions

diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 714a3e47bbe8..9adc202fcd6f 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -30,6 +30,7 @@ enum {
         FAULT_INFO_RATE,        /* struct f2fs_fault_info */
         FAULT_INFO_TYPE,        /* struct f2fs_fault_info */
 #endif
+        RESERVED_BLOCKS,
 };
 
 struct f2fs_attr {
@@ -51,7 +52,7 @@ static unsigned char *__struct_ptr(struct f2fs_sb_info *sbi, int struct_type)
                 return (unsigned char *)SM_I(sbi)->dcc_info;
         else if (struct_type == NM_INFO)
                 return (unsigned char *)NM_I(sbi);
-        else if (struct_type == F2FS_SBI)
+        else if (struct_type == F2FS_SBI || struct_type == RESERVED_BLOCKS)
                 return (unsigned char *)sbi;
 #ifdef CONFIG_F2FS_FAULT_INJECTION
         else if (struct_type == FAULT_INFO_RATE ||
@@ -111,6 +112,17 @@ static ssize_t f2fs_sbi_store(struct f2fs_attr *a,
         if (a->struct_type == FAULT_INFO_TYPE && t >= (1 << FAULT_MAX))
                 return -EINVAL;
 #endif
+        if (a->struct_type == RESERVED_BLOCKS) {
+                spin_lock(&sbi->stat_lock);
+                if ((unsigned long)sbi->total_valid_block_count + t >
+                                (unsigned long)sbi->user_block_count) {
+                        spin_unlock(&sbi->stat_lock);
+                        return -EINVAL;
+                }
+                *ui = t;
+                spin_unlock(&sbi->stat_lock);
+                return count;
+        }
         *ui = t;
         return count;
 }
@@ -165,6 +177,7 @@ F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_no_gc_sleep_time, no_gc_sleep_time);
 F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_idle, gc_idle);
 F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, reclaim_segments, rec_prefree_segments);
 F2FS_RW_ATTR(DCC_INFO, discard_cmd_control, max_small_discards, max_discards);
+F2FS_RW_ATTR(RESERVED_BLOCKS, f2fs_sb_info, reserved_blocks, reserved_blocks);
 F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, batched_trim_sections, trim_sections);
 F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, ipu_policy, ipu_policy);
 F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_ipu_util, min_ipu_util);
@@ -208,6 +221,7 @@ static struct attribute *f2fs_attrs[] = {
         ATTR_LIST(inject_type),
 #endif
         ATTR_LIST(lifetime_write_kbytes),
+        ATTR_LIST(reserved_blocks),
         NULL,
 };